Another Life: At the edge of Ireland, a window on the universe

A couple of winters after moving to Mayo I reported Venus to the Garda Síochána. There she was, on a starry February night, lying right on the sea's horizon and flickering with vivid flames, red, white and blue, in the unsteady eye of my binoculars.

I just thought, as I told the Louisburgh sergeant (we had one back then), that it might be a ship on fire or sending up flares. He called back, having checked with the coast guard, to reassure me.

Venus has apparently done other dramatic things lately, arriving at its perihelion, its closest point to the sun, and keeping an eight-yearly rendezvous with Spica, a whirling dumb-bell of two stars, each bigger and hotter than the sun. But, as I write, the weather has been doing some whirling of its own, blanking out the night sky and any glimpse of its brightest planet.

My pleasure in the stars is thus of the lyrical and gobsmacked variety rather than the astronomical. The privilege of living with so frequent and so stunning a window on the universe has been a profound reward of living at the western edge. Even coming up to Christmas, as reindeer gallop up gables and shining icicles chase around walls, most of Mayo stays blessedly dark on the twirling disco ball of the world lit up at night.

The darkest spot of all must be somewhere on Nephin mountain, the great, shadowy backdrop to Ballycroy National Park and its 11,000 hectares of wilderness. That this should also become a gold-starred International Dark-Sky Park as designated by the International Dark-Sky Association (darksky.org) is the ambition of an eager project team with much national and local support.

A central figure is Georgia MacMillan, who, changing lifestyle in her mid-40s, has recently earned an honours degree in outdoor education at Galway-Mayo Institute of Technology in Castlebar. Research for her dissertation on the effects of light pollution and preserving the clarity of night skies involved long-term measurement of the darkness of Ballycroy nights.

This was done with readings from an SQM, a sky quality meter used by astronomers, which converts available light into magnitudes-per-square-arc-second, or "mpsas": a really dark place scores more than 21. With meters on loan from Dr Brian Espey, an astrophysicist at Trinity College Dublin, the most sustained readings were above 21, recorded at a hillwalkers' hut on the Bangor trail, remote from towns and farm lights.

The Mayo project follows another in Co Kerry (kerrydarksky.com), designated the first gold tier Dark-Sky Reserve in the northern hemisphere, covering most of the Iveragh Peninsula. While Mayo can offer a park with public ownership and protection, Kerry's reserve depends on landowners and planners to preserve the quality of its darkness.

The reward, of course, is the promise of attracting, in winter, star-gazing tourists strung with binoculars or setting up tripods and telescopes.

The Kerry reserve sprang from the efforts of South-West Kerry Astronomy Group (south-kerry-astronomy-group.ie). A similar, if more modest, initiative is under way in Tipperary, where Shannonside Astronomy Club (shannonsideastronomyclub.com) has hopes of a "dark-sky park" centred on Lough Gur, Co Limerick, which has yielded the crucial SQM reading of 21.1.

All this finds support from Dark Sky Ireland (darksky.ie), which, like Georgia MacMillan, finds even more value in an unpolluted night than in filling B&Bs with star-struck winter hobbyists. Both are informed by research into the effects of light pollution on wildlife, plants and human health and happiness – light pollution disrupts the circadian cycle of night and day.

The toll on migrating birds of collision with lit buildings has been familiar, but the more subtle damage to wildlife of constant and diffusing light has now come under scrutiny. It disrupts the feeding and breeding cycles of insects, hormone rhythms of frogs, timings of flowers and leaf fall, survival of nocturnal animals and much more.

A lot depends on the way public light is used, on its shielding from the sky – even, it now seems, on its colour. As part of the Ballycroy project another graduate of GMIT, Gerard Dowling, is working on a light-management plan that offers dark-sky-friendly options to local communities and the county council.

Official dealings with the Republic’s 420,000 public lights are first concerned with saving energy, and Mayo, as it happens, has been pioneering a trial of control by computerised “dimming and trimming” of street lights in the town of Crossmolina.

Another economically attractive option is LED street lights, which save energy and reduce sky glow. But the white-blue colour of their light can, it seems, raise stress levels in nearby nesting songbirds and upset their circadian rhythms.

I am frankly not surprised – the glare of LED yard lights is quite ghastly – and would agree with warming up the tone (but not, please, to the dispiriting sodium ambers of the past).

Michael Viney's Reflections on Another Life, a selection of columns from the past four decades, is available from irishtimes.com/irishtimesbooks